DAC verification – practical method for testing a digital-to-analog converter What is the basic, effective approach to test a D/A converter over its operating range?

Introduction / Context:
Testing DACs involves verifying monotonicity, resolution, and linearity. A practical bench method examines the converter's response to all digital input codes and inspects the analog output for expected behavior.

Given Data / Assumptions:

• D/A converter under test; output can be observed on an oscilloscope or precision DMM.
• Full digital input code range is available.
• We want a quick but thorough functional check.

Concept / Approach:
Feeding the DAC a count sequence from 0 to full scale and plotting output versus time should yield a monotonic staircase that approximates a straight ramp after filtering. This reveals missing codes, nonlinearity, glitches, and monotonicity violations. Spot checks at only two points (zero and full scale) do not validate intermediate behavior.

Step-by-Step Solution:

Verification / Alternative check:
Alternatively, capture pairs (digital code, analog output) and compute INL/DNL numerically; the oscilloscope method is a fast qualitative equivalent.

Why Other Options Are Wrong:

• Single-step with DMM: Better than two points, but too slow and still easy to miss dynamic issues/glitches.
• Zero and full scale only: Does not detect missing codes or nonlinearity.
• Applying analog to DAC and checking digital: Reversed; that describes ADC testing.

Common Pitfalls:

• Using insufficient settling time per code and misinterpreting transient glitches as errors.
• Failing to ensure reference stability and low-noise grounding during measurement.

Final Answer:
apply a sequence of binary codes covering the full range … linear stairstep ramp